Method of preparing paper stock for application of a moisture-resistant material



March 3, 1942.

R. E. HORNBECK 2,275,148 METHOD OF PREPARING PAPER STOCK FOR APPLICATION OF A MOISTURE-RESISTANT MATERIAL Filed Nov. 1938 2' Sheets-Sheet l k A w R 1D a m M 58 m M EO SQ w m a r a Q m EG mx 5&3

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ATTORNEY March 1942- E. HO BECK 2,275,143 METHOD OF PREPAR PAPER 5 K FOR APPLICATION OF A MOISTURE"R STANT MATERIAL Filed v. 2, 1958 2 Sheets-Sh eet 2 lliiil in" ATTQRN EY Patented Mar. 3, E42

UNITED STATES PATENT METHOD OF PREPARING PAPER STOCK FOR APPLICATION OF A MOISTURE-RE- SISTANT MATERIAL Richard E. Hornbeck, Kansas City, Mo., assignor to Waxide Paper Company, Kansas City, Mo., a corporation of Missouri Application November 2, 1938, Serial No. 238,374

, 2,275,148 OFF [C E Claims.

This invention relates to a method of preparing tity to give the desired moisture-proofing efiectv The products, such as bread, are usually wrapped mechanically and the folds of the wrapper are sealed incidental to slight melting of the wax on the contact portions of the folds. It has been found that paper prepared in this manner is resilient and of somewhat springy character so that the folds tend to spring apart before the wax has set sufllciently to retain them in sealed condition. Often times the printing is elaborate and covers thiaentire area of the wrapper. The

fills in the pores and forms an unbroken. coveiing that prevents penetration of the wax and limits the amount that may be applied to the paper stock. Usually the coating over printed surfaces is 'not sufllciently' thick to effect adequate seal of the folds, which adds to the aggravating eflfects of the springy character of the paper and makes sealing more difflcult. This has. been overcome in part by leaving unprinted marinvention, as hereinafter pointed out, I have provided an improved method carried out with a novel apparatus illustrated in the accompanying drawings, wherein:

Figs. 1, 1A, 1B, 1C and 1D represent a 'diagrammatic section through the successive portions of the apparatus for treating base paper stock in accordance with the present invention.

Referring more in detail to the drawings:

l designates a roll of ordinary calendered and unprinted base paper from which wax paper is prepared in accordance with the present practice, and which is mounted in a printing press 2, having a plurality of guide rollers 3 for directing the paper between sets of printing rollers lfor print ing designs on the paper stock, usually in colored inks, such as are used in printing of bread wrappers. After printing the paper passes over rollers 5 and is rewound to form a roll 6.

The printing ink when applied to the surface I of the paper penetrates the pores thereof and forms a substantially smooth, unbroken covering over the surface of the paper in accordance with the design. I This ink covering limits the amount of water-proofing material that may be caused to penetrate the body of the paper, and I, therefore. provide for breaking up the continuous surface of the ink so that the printed portions of the paper have substantially the same surface texture'as ting machine and stored for a period of time to gins where the sealing folds are to be formed, but 39 the unprinted portions.

these margins are. not ordinarily desirable for the 4 The r lls f p p 6, fi r p n re reason that they destroy the artistic character of therefore placed in a wetting machine I wherein the design, particularly at the exposed end folds the roll is unwound and the printed paper guided of the wrapper. The ordinary waxed paper is over suitable rollers 8 and between driven rollers also brittle in character so that folding presents 9 a d I9 across a Wetting Z0116 H, provided n e unsightly crinkles in the wrapper. The printing mediate lower guide-rollers l2 and I3 respectively. appears dull and fiat and free of'highlights that Fr m th l w r l r B t pap s wound enhance the appearance of a wrapped product. n a roll All of these ill effects are more pronounced with ocate adj ce the p t o t e of t Daage of the-paper stock, particularly where it is 40 p a a Po between the. guide rollers d necessary to carry many sizes of paper stock on 13, is a wetting mechanism I5 which distributes hand due to market conditions, distance of the I the Wettin liq d unifo m y Ov r e p te .manufacturerfrom the source of paper supply side of the paper in an accurately controlled and other reasons. quantity to produce the desired results. The

It is. therefore, a'principal object of the present mechanism [5 includes a cylindrical brush l6 invention to prepare a wax paper that is of subhaving a plurali y of liis les adapted o mo stantially flexible character to eliminate creepinto wiping contact with the pickup roller l1 ing of the folds when a product is wrapped therein rotatable within a body of wetting liquid, such as and to facilitate sealing qualities thereof. water I8, that is carried in a pan IS. The brush Other important objects of the invention are to I6 is positioned relatively to the paper and roprovide amoisture-proof wax paper which is glostates at such a sp ed th t t w r p d p sier and of better appearance than that ordinarily from the roller l l is centrifugally discharged in produced; to provide a wax paper wherein the a fine mist onto the unprinted side of the paper printing does not interfere with application of the while it is P s between the rollers l2 and I3,

I required amount of "wax necessary in effecting a as cl ar y s own inth d aw The w tt ng seal; to produce a printed'paper stock wherein the medium is thus delivered tothe surface of the printing is of better appearance; and to provide paper so that there are no excessive wet spots a wax paper that is sufllciently pliable to'prevent on the paper. The wetted paper, after being cracking of the wax coating; wound upon the roll I4, is removed from the wet- In accomplishing these and other objects of the permit thorough and uniform penetration of the wetting medium into the body of the paper, as indicated by the rolls and 2|. The wetting medium increases the moisture content of the paper so that when again unrolled it is rendered extremely pliable and capable of being calendered to break down the smooth, continuous surface of the ink so that it has substantially the,

the paper is unwound therefrom over Spreaders 23 and 24 to stretch the paper so that it enters between the first of a stand of calender rolls 25 and a feed belt 26. The paper then passes alternately over successive calender rolls and is guided by a rollerl'l for rewinding into a roll 28. V The calender rolls press down and smooth out the paper to close thepores so that the moisture is retained therein and. the surfaces are given a which, when congealed, provides a substantially hermetically sealed wrapper. The wrapper, being very pliable, retains its folds until the wax has congealed. The printing colors are also clearly improved, the colors being substantially brighter and having highlights, which enhance the appearance of the wrapped article. The flexibility of the paper also prevents checking and marking of the wax and when the paper is used as wrappers they forrn fresh and attractive packages.

What I claim and desire to secure by Letters 3 Patent is:

glossier, smoother and far more finished appearance. Calendering of the paper breaks the filament of ink and later permits absorption of the water-proofing solution, as later described. The tone of the ink colors is also improved so that they are brighter and of more attractive appearance. The calender rolls are kept clean by the usual doctor blades 29 and are cooled by directing air thereon through nozzles 30 and 3| as shown in Fig. 1B.

On passage of the sheet through the calender stock some of the moisture is evaporated. but a substantial portion of the moisture held by the capillaries is transformed and retained through hydration of the fibres. The treated sheet is thus rendered smoothly dense, and has a greatly improved appearance after coating.

After being super-calendered the rolls 28 are then delivered to a coating machine, indicated in Fig. 10, wherein the paper is guided over rollers 32 and through a bath of coating solution 33, such as melted paraflin. After passing through'the coating solution, the paper is guided between rollers 34 and 35 which squeeze off excessive material and drain it back into the body of coating solution. From the'rollers 34 and 35 the paper is guided through a chilled water bath 36 where the shipping to the user.

When the paper is treated in accordance with the above described process, the wax coating penetrates substantially uniformly into the paper regardless of the printing, so that there is sumcient wax covering the"pri nting to effect sealthereof when the paper is used in wrapping various articles. For example, in the wrapping of bread, the rolls of paper 39 are used in a standard loaves of bread are successively wrapped and' the ends of the wrapper folded. Heat is applied to the folds of the Wrapper to cause slight melting of the wax on the contacting portions of the fold,

.wra'pping machinewherein wrappers are cut and 1. The method of preparing a paper base stock for application of a moisture resistant coating including, printing the paper base stock, wetting theprinted paper base stock with water, forming the wetted paper base stock into a roll to prevent evaporation of said water and effect penetration of the water into the paper base stock, storing the roll paper base stock for a time to complete said penetration, and calendering said printed base stock to render said paper base stock including the printed portions thereof absorbent to said moisture resistant coating. 1

2; The method of preparing a paper base stock for application of a coating material including, printing a calendered paper base stock, wetting the calendered paper base stock after printing with water, forming the wetted paper base stock into a roll to prevent evaporation of the water and effect penetration of the water into the base stock, and supercalendering the base stock to render the base stock and printing absorbent to said coating material.

3. The method of preparing a paper base stock for application of a moisture resistant coating material including, printing a calendered paper base stock, wetting one surface of the calendered paper base stock after printing with water, rolling up the wetted stock to bring the wetted surface into contact with the unwetted surface, allowing the roll to stand for a sufficient time for the water to thoroughly penetrate the base stock, and supercalendering the base stock to smooth the surfaces thereof and. render said printed portions absorbent to the water resistant material.

4. The method of preparinga paper base stock for application of a moisture resistant material including, printing the paper base stock, treating the base stock with water, rolling up the printed base stock for preventing evaporation of the water and effecting penetration of the water into the stock for rendering the stock sufficiently pliable for calendering, unrolling the base stock after the water has sufficiently penetrated the body of the stock, and calendering the base stock to reduce the surfaces of said printing so that the inked portions of the printing are rendered absorbent to a moisture resistant coating.

5. The method of preparing a paper base stock for application of a moisture resistant material including, printing a relatively dry calendered paper base stock, wetting'the base stock with water to increase the moisture content thereof, forming the base stock into a roll for effecting uniform penetration of added moisture to render 

